Synthetic jet with non-metallic blade structure

ABSTRACT

A system and method for lowering resonant frequency in a synthetic jet device for less noise, as well as lowering vibration, is disclosed. A synthetic jet device includes a first plate, a second plate spaced apart from the first plate, a spacing component coupled to and positioned between the first and second plates to form a chamber and including an orifice therein, and an actuator element coupled to at least one of the first or second plates to selectively cause deflection thereof, wherein the first and second plates are formed at least in part of a non-metallic material.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a non-provisional of, and claims priority to,U.S. Provisional Patent Application Ser. No. 61/787,738, filed Mar. 15,2013, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Synthetic jet actuators are a widely-used technology that generates asynthetic jet of fluid to influence the flow of that fluid over asurface to disperse heat away therefrom. A typical synthetic jetactuator comprises a housing defining an internal chamber. An orifice ispresent in a wall of the housing. The actuator further includes amechanism in or about the housing for periodically changing the volumewithin the internal chamber so that a series of fluid vortices aregenerated and projected in an external environment out from the orificeof the housing. Examples of volume changing mechanisms may include, forexample, a piston positioned in the jet housing to move fluid in and outof the orifice during reciprocation of the piston or a flexiblediaphragm as a wall of the housing. The flexible diaphragm is typicallyactuated by a piezoelectric actuator or other appropriate means.

Typically, a control system is used to create time-harmonic motion ofthe volume changing mechanism. As the mechanism decreases the chambervolume, fluid is ejected from the chamber through the orifice. As thefluid passes through the orifice, sharp edges of the orifice separatethe flow to create vortex sheets that roll up into vortices. Thesevortices move away from the edges of the orifice under their ownself-induced velocity. As the mechanism increases the chamber volume,ambient fluid is drawn into the chamber from large distances from theorifice. Since the vortices have already moved away from the edges ofthe orifice, they are not affected by the ambient fluid entering intothe chamber. As the vortices travel away from the orifice, theysynthesize a jet of fluid, i.e., a “synthetic jet.”

It is recognized that acoustic noise is one negative aspect of syntheticjet operation, including dual cooling jets (DCJs) that employ anactuator (i.e., piezoelectric actuator) on each of opposing surfaces ofthe device. DCJs are typically excited at or near their mechanicalresonance mode(s) in order to optimize electrical to mechanicalconversion and so as to achieve maximum deflection at minimal mechanicalenergy input. While DCJ operation is optimized when operated at or neartheir mechanical resonance mode(s), it is recognized that operating theDCJ at certain frequencies can generate a substantial amount of acousticnoise, as the acoustic signature of the device is in part determined bythe drive frequency of the device.

Synthetic jets of many variants, including the DCJ, are typicallyconstructed using a metalized piezo-actuator bonded to a metallic plateor blade with an electrically conductive adhesive. Electricalconnections to the piezo-actuator are achieved by connecting to themetalized exposed piezo side and connecting to the plate material.Solders or conductive adhesives are typically used. Two of these platesare then adhered together along the perimeter leaving an orifice openingto form the jet. Upon actuation of the piezo-actuators, air is inhaledand exhaled through the orifice causing a net positive air flow.

One drawback to metallic plates or blades is that they are expensive andtheir stiffness causes higher resonant frequencies that increase DCJoperating noise. In addition, the metal mass can cause increasedvibration. Still further, the resonant frequency of the DCJ can beincreased due to the metallic plates.

It would therefore be desirable to provide a synthetic jet, such as aDCJ, having plates that are fabricated to have much lower resonantfrequency for less noise. It would also be desirable for the plates tohave a reduced mass that can provide lower vibration.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of the invention, a synthetic jet deviceincludes a first plate, a second plate spaced apart from the firstplate, a spacing component coupled to and positioned between the firstand second plates to form a chamber and including an orifice therein,and an actuator element coupled to at least one of the first or secondplates to selectively cause deflection thereof, wherein the first andsecond plates are formed at least in part of a non-metallic material.

In accordance with another aspect of the invention, a method offabricating a synthetic jet device includes constructing a first plateand a second plate at least in part of a non-metallic material,attaching an actuator element to at least one of the first and secondplates to selectively cause deflection thereof, and positioning thefirst plate relative to the second plate by way of a spacing component,the spacing component securing the first plate to the second plate in aspaced apart arrangement to form a chamber and including an orificetherein. The method also includes attaching electrical connections tothe actuator element and the respective one of the first and secondplates to which the actuator element is attached so as to enable aselective applying of voltage to the actuator element.

In accordance with yet another aspect of the invention, a synthetic jetdevice includes a first plate, a second plate spaced apart from thefirst plate to form a chamber, and an actuator element coupled to atleast one of the first or second plates to selectively cause deflectionthereof so as to change a volume of the chamber. Each of the first andsecond plates includes a first material comprising an electricallyinsulating, non-metallic material and a second material comprising anelectrically conductive material, the second material being formed asone of a filler material, a metalizing layer, and internally orexternally formed leads provided on or in the first material.

These and other advantages and features will be more readily understoodfrom the following detailed description of preferred embodiments of theinvention that is provided in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate embodiments presently contemplated for carryingout the invention.

In the drawings:

FIGS. 1 and 2 are views of a synthetic jet assembly useable withembodiments of the invention.

FIG. 3 is a cross-section of the synthetic jet of FIGS. 1 and 2depicting the jet as the control system causes the diaphragms to travelinward, toward the orifice.

FIG. 4 is a cross-section of the synthetic jet of FIGS. 1 and 2depicting the jet as the control system causes the diaphragms to traveloutward, away from the orifice.

FIG. 5 illustrates a build-up process for fabricating a synthetic jetthat includes non-metallic plates therein, according to an embodiment ofthe invention.

FIG. 6 illustrates a build-up process for fabricating a synthetic jetthat includes non-metallic plates therein, according to an embodiment ofthe invention.

FIG. 7 illustrates a build-up process for fabricating non-metallicplates of a synthetic jet, according to an embodiment of the invention.

FIG. 8 illustrates a build-up process for fabricating non-metallicplates of a synthetic jet, according to an embodiment of the invention.

FIG. 9 illustrates a build-up process for fabricating a double-foldednon-metallic plate structure of a synthetic jet, according to anembodiment of the invention.

FIG. 10 illustrates a build-up process for fabricating double-foldednon-metallic plate structure of a synthetic jet, according to anembodiment of the invention.

FIG. 11 illustrates a build-up process for fabricating non-metallicplates of a synthetic jet, according to an embodiment of the invention.

DESCRIPTION OF THE INVENTION

Embodiments of the invention are directed to a synthetic jet devicehaving non-metallic plates that provide for a lower resonant frequencyfor less noise, as well as lower vibration.

FIGS. 1-4 illustrate a general structure of a synthetic jet assembly 10useable with embodiments of the present invention, along with themovement of various components during operation thereof, for purposes ofbetter understanding the invention. While a specific synthetic jetassembly 10 is illustrated in FIGS. 1-4, it is recognized thatembodiments of the invention may be incorporated into synthetic jetassemblies of varied constructions, and thus the synthetic jet assembly10 is not meant to limit the scope of the invention. As an example,synthetic jet assemblies that do not include a mounting bracket forsecuring positioning a synthetic jet are considered to be within thescope of the invention.

Referring first to FIG. 1, the synthetic jet assembly 10 is shown asincluding a synthetic jet 12, a cross-section of which is illustrated inFIG. 2, and a mounting bracket 14. In one embodiment, mounting bracket14 is a u-shaped mounting bracket that is affixed to a body or housing16 of synthetic jet 12 at one or more locations, although it isrecognized that the mounting bracket may be constructed as a brackethaving a different shape/profile, such as a semi-circular bracketconfigured to receive a circular synthetic jet 12 therein. A circuitdriver 18 can be externally located or affixed to mounting bracket 14.Alternatively, circuit driver 18 may be remotely located from syntheticjet assembly 10.

Referring now to FIGS. 1 and 2 together, and as shown therein, housing16 of synthetic jet 12 defines and partially encloses an internalchamber or cavity 20 having a gas or fluid 22 therein. While housing 16and internal chamber 20 can take virtually any geometric configurationaccording to various embodiments of the invention, for purposes ofdiscussion and understanding, housing 16 is shown in cross-section inFIG. 2 as including a first plate 24 and a second plate 26 (alternatelyreferred to as blades or foils), which are maintained in a spaced apartrelationship by a spacer element 28 positioned therebetween. In oneembodiment, spacer element 28 maintains a separation of approximately 1mm between first and second plates 24, 26. One or more orifices 30 areformed between first and second plates 24, 26 and the side walls ofspacer element 28 in order to place the internal chamber 20 in fluidcommunication with a surrounding, exterior environment 32. In analternative embodiment, spacer element 28 includes a front surface (notshown) in which one or more orifices 30 are formed.

According to various embodiments, first and second plates 24, 26 may beformed from a metal, plastic, glass, and/or ceramic. Likewise, spacerelement 28 may be formed from a metal, plastic, glass, and/or ceramic.Suitable metals include materials such as nickel, aluminum, copper, andmolybdenum, or alloys such as stainless steel, brass, bronze, and thelike. Suitable polymers and plastics include thermoplastics such aspolyolefins, polycarbonate, thermosets, epoxies, urethanes, acrylics,silicones, polyimides, and photoresist-capable materials, and otherresilient plastics. Suitable ceramics include, for example, titanates(such as lanthanum titanate, bismuth titanate, and lead zirconatetitanate) and molybdates. Furthermore, various other components ofsynthetic jet 12 may be formed from metal as well.

According to an exemplary embodiment, actuators 34, 36 are coupled torespective first and second plates, 24, 26 to form first and secondcomposite structures or flexible diaphragms 38, 40, which are controlledby driver 18 via a controller assembly or control unit system 42. Thesynthetic jet 12 is thus constructed as a DCJ. For controlling thediaphragms 38, 40, each flexible diaphragm 38, 40 may be equipped with ametal layer and a metal electrode may be disposed adjacent to the metallayer so that diaphragms 38, 40 may be moved via an electrical biasimposed between the electrode and the metal layer. As shown in FIG. 1,in one embodiment controller assembly 42 is electronically coupled todriver 18, which is coupled directly to mounting bracket 14 of syntheticjet 12. In an alternative embodiment control unit system 42 isintegrated into a driver 18 that is remotely located from synthetic jet12. Moreover, control system 42 may be configured to generate theelectrical bias by any suitable device, such as, for example, acomputer, logic processor, or signal generator.

In one embodiment, actuators 34, 36 are piezoelectric motive(piezomotive) devices that may be actuated by application of a harmonicalternating voltage that causes the piezomotive devices to rapidlyexpand and contract. During operation, control system 42 transmits anelectric charge, via driver 18, to piezoelectric actuators 34, 36, whichundergo mechanical stress and/or strain responsive to the charge. Thestress/strain of piezomotive actuators 34, 36 causes deflection ofrespective first and second plates 24, 26 such that a time-harmonic orperiodic motion is achieved that changes the volume of the internalchamber 20 between plates 24, 26. According to one embodiment, spacerelement 28 can also be made flexible and deform to change the volume ofinternal chamber 20. The resulting volume change in internal chamber 20causes an interchange of gas or other fluid between internal chamber 20and exterior volume 32, as described in detail with respect to FIGS. 3and 4.

Piezomotive actuators 34, 36 may be monomorph or bimorph devices,according to various embodiments of the invention. In a monomorphembodiment, piezomotive actuators 34, 36 may be coupled to plates 24, 26formed from materials including metal, plastic, glass, or ceramic. In abimorph embodiment, one or both piezomotive actuators 34, 36 may bebimorph actuators coupled to plates 24, 26 formed from piezoelectricmaterials. In an alternate embodiment, the bimorph may include singleactuators 34, 36, and plates 24, 26 are the second actuators.

The components of synthetic jet 12 may be adhered together or otherwiseattached to one another using adhesives, solders, and the like. In oneembodiment, a thermoset adhesive or an electrically conductive adhesiveis employed to bond actuators 34, 36 to first and second plates, 24, 26to form first and second composite structures 38, 40. In the case of anelectrically conductive adhesive, an adhesive may be filled with anelectrically conductive filler such as silver, gold, and the like, inorder to attach lead wires (not shown) to synthetic jet 12. Suitableadhesives may have a hardness in the range of Shore A hardness of 100 orless and may include as examples silicones, polyurethanes, thermoplasticrubbers, and the like, such that an operating temperature of 120 degreesor greater may be achieved.

In an embodiment of the invention, actuators 34, 36 may include devicesother than piezoelectric motive devices, such as hydraulic, pneumatic,magnetic, electrostatic, and ultrasonic materials. Thus, in suchembodiments, control system 42 is configured to activate respectiveactuators 34, 36 in corresponding fashion. For example, if electrostaticmaterials are used, control system 42 may be configured to provide arapidly alternating electrostatic voltage to actuators 34, 36 in orderto activate and flex respective first and second plates 24, 26.

The operation of synthetic jet 12 is described with reference to FIGS. 3and 4. Referring first to FIG. 3, synthetic jet 12 is illustrated asactuators 34, 36 are controlled to cause first and second plates 24, 26to move outward with respect to internal chamber 20, as depicted byarrows 44. As first and second plates 24, 26 flex outward, the internalvolume of internal chamber 20 increases, and ambient fluid or gas 46rushes into internal chamber 20 as depicted by the set of arrows 48.Actuators 34, 36 are controlled by control system 42 so that when firstand second plates 24, 26 move outward from internal chamber 20, vorticesare already removed from edges of orifice 30 and thus are not affectedby the ambient fluid 46 being drawn into internal chamber 20. Meanwhile,a jet of ambient fluid 46 is synthesized by vortices creating strongentrainment of ambient fluid 46 drawn from large distances away fromorifice 30.

FIG. 4 depicts synthetic jet 12 as actuators 34, 36 are controlled tocause first and second plates 24, 26 to flex inward into internalchamber 20, as depicted by arrows 50. The internal volume of internalchamber 20 decreases, and fluid 22 is ejected as a cooling jet throughorifice 30 in the direction indicated by the set of arrows 52 toward adevice 54 to be cooled, such as, for example a light emitting diode. Asthe fluid 22 exits internal chamber 20 through orifice 30, the flowseparates at the sharp edges of orifice 30 and creates vortex sheetswhich roll into vortices and begin to move away from edges of orifice30.

While the synthetic jet of FIGS. 1-4 is shown and described as having asingle orifice therein, it is also envisioned that embodiments of theinvention may include multiple orifice synthetic jet actuators.Additionally, while the synthetic jet actuators of FIGS. 1-4 are shownand described as having an actuator element included on each of firstand second plates, it is also envisioned that embodiments of theinvention may include only a single actuator element positioned on oneof the plates. Furthermore, it is also envisioned that the synthetic jetplates may be provided in a circular, rectangular, or alternativelyshaped configuration, rather than in a square configuration asillustrated herein.

According to embodiments of the invention, a synthetic jet device isprovided that includes plates or blades that are formed in-part orin-whole of a non-metallic material—and thus are generally referred tohereafter as “non-metallic plates.” The plates can be formed from any ofa number of suitable non-metallic materials that may be selected andtailored to set the stiffness and thus adjust the resonant frequency ofthe synthetic jet. By selecting a specific non-metallic material fromwhich to form the plates in-part or in-whole, the plates can befabricated to have much lower resonant frequency for less noise and areduced mass that can provide lower vibration.

According to embodiments of the invention, the non-metallic materialfrom which the plate is formed in-part or in-whole can be a number ofsuitable non-metallic materials, such as (but not limited to): athermoplastic or thermoset in the form of polyethylene, polypropylene,polystyrene, polyvinyl chloride, and polytetrafluoroethylene (PTFE),Polyethylene terephthalate (PET), Polyethylene (PE), High-densitypolyethylene (HDPE), Polyvinyl chloride (PVC), Polyvinylidene chloride(PVDC) Low-density polyethylene (LDPE), Polypropylene (PP) Polystyrene(PS), High impact polystyrene (HIPS) Polyamides (PA) Acrylonitrilebutadiene styrene (ABS) Polycarbonate (PC) Polycarbonate/AcrylonitrileButadiene Styrene (PC/ABS) Polyurethanes (PU), Epoxies and combinationsthereof, including combinations of various thermoplastics, thermosetsand fillers. The fillers loading the plastic can include electricallyconductive and insulating fillers such as silver particles, ceramics,glasses, etc. In forming the plates, common practices such as casting orinjection molding may be employed.

In some embodiments of the invention, a metallic coating is applied to aplate formed of non-metallic material. In other embodiments of theinvention, the plate can be made sufficiently electrically conductive(via use of a filler) so that a metallic coating is not necessary.

Referring to FIG. 5, a build-up process for fabricating a non-metallicplate 60 (and synthetic jet 12) is shown according to one embodiment ofthe invention. In a first step of the process, a non-metallic andelectrically insulating material or substrate 60 is provided, such as asubstrate formed of any of the thermoplastic or thermoset materials setforth above. In a next step, the non-metallic substrate 62 is dipped ina catalyst (e.g., palladium catalyst), as indicated at 64, to activate asurface/backside protect for the plate. A metallic material that iselectrically conducting, such as copper or nickel, is then applied viaelectroless plating in a next step, as indicated at 66, to form thefinal structure of the non-metallic plate 60. Upon plating, a conductiveepoxy (e.g., Ag epoxy) is utilized to secure a piezomotive actuator 34,36 to the plate 60. Finally, electrical conduits 68, such as wires orflex circuit material, are attached to the piezomotive actuator 34, 36and the plate 60. An adhesive, such as silicon, can then be used to jointhe two plates 60 of the synthetic jet together—with the silicon formingthe spacer element 28 between the two plates of the synthetic jet 12that is formed.

With respect to the process illustrated and described in FIG. 5,processing alternate to electroless plating, such as evaporation orsputtering techniques, can be used to deposit the metal. Electroplatingcan then follow if a thicker metal is desired. Typical metallizationschemes may include palladium activated electroless copper or nickel,sputtered or evaporated Ti, Cr, TiW, Cu, Ni, Au, Al followed by thickerplating of Cu, or Ni capped with a thin Au layer (if needed to preventoxidation). Sputtered or evaporated processes will typically start withdeposition of Ti, Cr, or TiW to promote metal adhesion. The finishedmetal can be patterned if desired using shadow masking or commonlithographic pattern and etch steps. In another embodiment, the platemay be cast from a piezo-polymer material, metalized on both sides andpolarized to form an integral actuator plate.

Referring now to FIG. 6, another example of a non-metallic plate(s) 70(and a build-up process for fabrication of a synthetic jet 12) is shownaccording to an embodiment of the invention. The non-metallic plates 70in FIG. 6 are formed as a thin single-sided copper coatedglass-reinforced epoxy laminate sheet (e.g., FR4 PCB blanks)—alternatelyreferred to hereafter as copper coated PCB blanks. In fabrication of thesynthetic jet 12, the copper coated PCB blanks 70 are provided and aconductive epoxy (e.g., Ag epoxy) and piezo-actuator 34, 36 are thensubsequently applied thereto, with the epoxy securing the piezo-actuator34, 36 to the copper coating of the non-metallic plates 70. Electricalconduits 68, such as urethane coated wires, are then attached to thepiezo element and the copper coated PCB blanks 70 (e.g., soldered,conductive epoxied, or mechanically attached), with an adhesive such assilicon 28 applied along a perimeter of the plates 70 used to join thetwo plates of the synthetic jet 12 together—the silicon 28 sealing theplates 70 together while also leaving an aperture or orifice therein.

In other embodiments of the invention, the non-metallic plates of thesynthetic jet 12 may be formed of Kapton® or another suitable dielectricmaterial. One embodiment where Kapton plates are utilized for formingnon-metallic plates is provided in FIG. 7, where a build-up process forfabrication of the plate(s) is illustrated. As shown in the build-upprocess of FIG. 7, for each non-metallic plate, a bare Kapton plate 72is first provided, with a conductive lead 74 then being formed on thetop surface 76 thereof—in the form of a sputtered lead, Kaptonconnector, wire, or line of conductive epoxy. In a next step of thebuild-up process, a piezo-actuator 34, 36 is placed on each Kapton plate72 so as to be electrically coupled to the conductive lead 74. Finally,electrical connections 68 are provided for connection to thepiezo-actuators 34, 36 and the conductive leads 68. An adhesive, such assilicon, can then be used to join the two plates of the synthetic jettogether—with the silicon forming the spacer element between the twoplates of the synthetic jet.

In another embodiment where Kapton plates are utilized, and as shown inthe build-up process of FIG. 8, non-metallic plates 78 are provided thatare each constructed as a Kapton circuit—with a thicker layer of Kaptonbeing provided with internal wiring 80 therein that can connect to thepiezo-actuator 34, 36. The internal wiring 80 can be completely coveredby Kapton and exposed locally at the piezo-actuator 34, 36 and leadcontacts (for connection of electrical conduits 68), or can be exposedentirely.

Referring now to FIGS. 9 and 10, in additional embodiments of theinvention, the non-metallic plates of a synthetic jet are made out of asingle piece of non-metallic material that is folded double at a bridgeportion to form a pair of plates. Referring first to the build-upprocess of FIG. 9, a double-folded plate is fabricated by firstproviding a single piece of non-metallic material (e.g., Kapton) 82 thatis folded double at a bridge portion 84 to define a pair of plateportions 86, 88. As shown in FIG. 9, the bridge portion 84 is formed asa thin strip of material that is centered along a width of the plates86, 88. It is recognized, however, that the bridge portion 84 couldinstead be formed to extend a full width of the plates 86, 88 but beconfigured to provide for a folding thereof to generally in defineseparate first and second plates 86, 88. According to an exemplaryembodiment, the double-folded plate 82 includes internal electricalconnections or leads formed therein that are covered and exposed locallyat the piezo-actuators and lead contacts.

In the embodiment of FIG. 9, the internal wiring includes a continuouslead 90 that extends between the two piezo-actuators 34, 36 that arepositioned on the respective plates 86, 88 and connects to each of thepiezo-actuators 34, 36—such that the number of internal leads formed inthe double-folded plate is reduced. The number of electrical connections68 provided for connection to the synthetic jet is also reduced, asconnections 68 are only needed for each of the two piezo-actuators 34,36 and for the continuous conductive lead 90 that extends across thebridge portion 84—for a total of three electrical connections 68 to thesynthetic jet.

In an alternative embodiment of the double-folded plate of FIG. 9 (andthe continuous lead shown therein extending across the bridge portion),FIG. 10 shows a double-folded plate 82 having a discontinuous leadthrough the bridge portion—such that two separate leads 92 are defined.The separate leads 92 are connected to the two piezo-actuators 34, 36positioned on the respective plates 86, 88, with electrical connections68 being provided for connection to the two piezo-actuators 34, 36 andfor the conductive leads 92. Thus, in the embodiment of FIG. 10, a totalof four electrical connections 68 are provided for to the synthetic jet.

Referring now to FIG. 11, another example of a non-metallic plate 94(and a build-up process for fabrication thereof) is shown according toan embodiment of the invention. A plate 94 is provided that is formedout of non-metallic, non-conductive material, such as Kapton. Each plate94 that is provided has a metallic hole 96 formed therein that islocated so as to be positioned under a respective piezo-actuator 34, 36that is to be positioned on the plate 94, as shown on the front and backsurfaces 98, 100 of the plate in FIG. 11. This hole 96 may be filledwith a metallic insert or conductive epoxy to form an electricalconnection to the backside of the piezo-actuator 34, 36 that ispositioned on the front surface 98 of a respective plate 94. Anelectrical flex circuit or sputtered line contact 102 is formed on theback surface 100 of the plate 94 to bring the electrical signal to aposition where wires or flex circuit leads 68 can be attached to thesynthetic jet 12.

Beneficially, embodiments of the invention thus provide a synthetic jetassembly that incorporates non-metallic plates to lower a level ofacoustic noise during operation of the synthetic jet. The non-metallicplates are fabricated to have a lower stiffness than metallic plates soas to provide a lower resonant frequency that generates less noise, withthe plates also having a reduced mass that provides lower vibrationduring operation. The non-metallic plates may be formed of inexpensivematerials such that the cost thereof is reduced as compared to metallicplates.

Therefore, according to one embodiment of the invention, a synthetic jetdevice includes a first plate, a second plate spaced apart from thefirst plate, a spacing component coupled to and positioned between thefirst and second plates to form a chamber and including an orificetherein, and an actuator element coupled to at least one of the first orsecond plates to selectively cause deflection thereof, wherein the firstand second plates are formed at least in part of a non-metallicmaterial.

According to another aspect of the invention, a method of fabricating asynthetic jet device includes constructing a first plate and a secondplate at least in part of a non-metallic material, attaching an actuatorelement to at least one of the first and second plates to selectivelycause deflection thereof, and positioning the first plate relative tothe second plate by way of a spacing component, the spacing componentsecuring the first plate to the second plate in a spaced apartarrangement to form a chamber and including an orifice therein. Themethod also includes attaching electrical connections to the actuatorelement and the respective one of the first and second plates to whichthe actuator element is attached so as to enable a selective applying ofvoltage to the actuator element.

According to yet another aspect of the invention, a synthetic jet deviceincludes a first plate, a second plate spaced apart from the first plateto form a chamber, and an actuator element coupled to at least one ofthe first or second plates to selectively cause deflection thereof so asto change a volume of the chamber. Each of the first and second platesincludes a first material comprising an electrically insulating,non-metallic material and a second material comprising an electricallyconductive material, the second material being formed as one of a fillermaterial, a metalizing layer, and internally or externally formed leadsprovided on or in the first material.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

What is claimed is:
 1. A synthetic jet device comprising: a first plate;a second plate spaced apart from the first plate; a spacing componentcoupled to and positioned between the first and second plates to form achamber and including an orifice therein; and an actuator elementcoupled to at least one of the first or second plates to selectivelycause deflection thereof; wherein the first and second plates are formedat least in part of a non-metallic material.
 2. The synthetic jet deviceof claim 1 wherein the non-metallic material comprises an electricallynon-conductive material.
 3. The synthetic jet device of claim 2 whereinthe non-metallic material comprises at least one of a thermoplastic,thermoset, and a filler material.
 4. The synthetic jet device of claim 2wherein each of the first and second plates includes an electricallyconductive metallic material, the electrically conductive metallicmaterial comprising one of a filler material, a metalizing layer, andinternally or externally formed leads.
 5. The synthetic jet device ofclaim 4 wherein each of the first and second plates comprises: anelectrically non-conductive, non-metallic substrate; and an electricallyconductive metalizing layer applied onto the electricallynon-conductive, non-metallic substrate.
 6. The synthetic jet device ofclaim 4 wherein each of the first and second plates comprises acopper-plated printed circuit board (PCB) blank.
 7. The synthetic jetdevice of claim 4 wherein each of the first and second plates comprises:a flexible dielectric layer; and electrically conductive leads formed onan exterior surface of the flexible dielectric layer or internallywithin the flexible dielectric layer.
 8. The synthetic jet device ofclaim 1 wherein the first and second plates comprise a single piece ofnon-metallic material folded along a bridge thereof to form the firstand second plates.
 9. The synthetic jet device of claim 8 wherein acontinuous electrically conductive lead is formed internally in thesingle piece of non-metallic material and extends through the bridge andto the actuator element on the respective first and second plates. 10.The synthetic jet device of claim 8 wherein a discontinuous electricallyconductive lead is formed internally in the single piece of non-metallicmaterial and extends through the bridge and to the actuator element onthe first and second plates.
 11. A method of fabricating a synthetic jetdevice comprising: constructing a first plate and a second plate atleast in part of a non-metallic material; attaching an actuator elementto at least one of the first and second plates to selectively causedeflection thereof; positioning the first plate relative to the secondplate by way of a spacing component, the spacing component securing thefirst plate to the second plate in a spaced apart arrangement to form achamber and including an orifice therein; and attaching electricalconnections to the actuator element and the respective one of the firstand second plates to which the actuator element is attached so as toenable a selective applying of voltage to the actuator element.
 12. Themethod of claim 11 wherein constructing each of the first plate and thesecond plate comprises selecting a material composition of the first andsecond plates to set a stiffness of the first and second plates to adesired amount, so as to adjust a resonant frequency of the syntheticjet device to a desired level.
 13. The method of claim 11 whereinconstructing each of the first plate and the second plate comprises:providing an electrically non-conductive, non-metallic substrate; andapplying an electrically conductive metalizing layer onto theelectrically non-conductive, non-metallic substrate.
 14. The method ofclaim 11 wherein constructing each of the first plate and the secondplate comprises providing a copper-plated printed circuit board (PCB)blank.
 15. The method of claim 11 wherein constructing each of the firstplate and the second plate comprises providing an electricallynon-conductive, non-metallic material having an electrically conductivefiller material mixed therein.
 16. The method of claim 11 whereinconstructing each of the first plate and the second plate comprisesproviding a flexible dielectric layer that includes electricallyconductive leads formed on an exterior surface of the flexibledielectric layer or internally within the flexible dielectric layer, theelectrically conductive leads providing for electrical coupling of theactuator element and the electrical connections thereto.
 17. The methodof claim 11 wherein constructing the first plate and the second platecomprises: providing a single piece of electrically non-conductive,non-metallic material comprising a first plate portion, a second plateportion, and a bridge portion; and folding the single piece ofelectrically non-conductive, non-metallic material at the bridge portionto orient the first plate portion in a substantially parallelarrangement with the second plate portion, so as to form the first plateand the second plate; wherein the single piece of electricallynon-conductive, non-metallic material includes one of a lead formedinternally therein that extends through the bridge portion and to theactuator element on the at least one of the first and second plates. 18.The method of claim 17 wherein the lead formed internally in the singlepiece of electrically non-conductive, non-metallic material comprisesone of a continuous lead and a non-continuous lead.
 19. A synthetic jetdevice comprising: a first plate; a second plate spaced apart from thefirst plate to form a chamber; and an actuator element coupled to atleast one of the first or second plates to selectively cause deflectionthereof so as to change a volume of the chamber; wherein each of thefirst and second plates comprises: a first material comprising anelectrically insulating, non-metallic material; and a second materialcomprising an electrically conductive material, the second materialbeing formed as one of a filler material, a metalizing layer, andinternally or externally formed leads provided on or in the firstmaterial.
 20. The synthetic jet device of claim 19 further comprising aspacing component coupled to and positioned between the first and secondplates to maintain the first and second plates in a spaced apartrelationship, wherein the first plate, second plate and spacingcomponent collectively form the chamber and wherein the spacingcomponent includes an orifice therein.
 21. The synthetic jet device ofclaim 19 wherein the first and second plates comprise a folded platestructure formed of a single piece of electrically non-conductive,non-metallic material, the folded plate structure including: a firstplate portion; a second plate portion; a bridge portion connecting thefirst plate portion to the second plate portion; and a lead formedinternally in the double-folded plate structure that extends through thebridge portion and to the actuator element on the at least one of thefirst and second plates; wherein the folded plate structure is folded atthe bridge portion to orient the first plate portion in a substantiallyparallel arrangement with the second plate portion so as to form thefirst plate and the second plate.
 22. The synthetic jet device of claim19 wherein the composition of the first and second materials in each ofthe first plate and the second plate sets a stiffness of the first andsecond plates to a pre-determined amount, so as to set a resonantfrequency of the synthetic jet device at a desired level.